Fluorine containing hydrohalocarbons are of current interest due to their potential to replace ozone depleting chlorofluorocarbons, which are used in a variety of applications including refrigerants, propellants, blowing agents, and solvents. Both HCFC-235fa and HFC-245fa are known to be useful as blowing agents. HFC-245fa has physical properties, including a boiling point of about 14.degree. C., that makes it particularly attractive as a blowing agent, refrigerant or propellant. Its ability to function in a manner similar to CFC-11 (CCl.sub.3 F, b.p. 24.degree. C.), a well known aerosol propellant at the time, was noted by Smith and Woolf in U.S. Pat. No. 2,942,036 (1960). European Patent Application EP 381 986 also states (using a generic formula) that CF.sub.3 CH.sub.2 CF.sub.2 H may be used as a propellant or blowing agent. The use of HFC-245fa as a heat transfer agent is also mentioned in JP 02/272,086 (Chem. Abstr. 1991, 114, 125031q).
Previously, CF.sub.3 CH.sub.2 CF.sub.2 Cl has been prepared by a liquid phase reaction of 1,1,1,3,3,3-hexachloropropane with HF in the presence of a catalyst, as disclosed in EP 0 522 639.
Commonly assigned U.S. Pat. No. 5,728,904 discloses the preparation CF.sub.3 CH.sub.2 CF.sub.2 Cl by fluorination of CCl.sub.3 CH.sub.2 CCl.sub.3 with HF in the presence of either TiCl.sub.4 or SnCl.sub.4 catalysts, followed by reduction to HFC-245fa.
The preparation of CF.sub.3 CH.sub.2 CF.sub.2 Cl by the BF.sub.3 -catalyzed addition of HF to CF.sub.3 CH.dbd.CFCl is also known (R. C. Arnold, U.S. Pat. No. 2,560,838; 1951). The source of CF.sub.3 CH.dbd.CFCl was not disclosed.
HFC-245fa was first made by the reduction of CF.sub.3 CCl.sub.2 CF.sub.2 Cl over a palladium catalyst (Smith and Woolf, U.S. Pat. No. 2,942,036, 1960). Materials exiting the reaction zone include CF.sub.3 CH.sub.2 CHF.sub.2, CF.sub.3 CH.dbd.CF.sub.2, CF.sub.3 CCl.dbd.CF.sub.2, and unreacted starting material. The desired CF.sub.3 CH.sub.2 CF.sub.2 H was formed in yields up to about 60%, but the source of the starting material was not disclosed.
Reduction of 1,1,1,3,3-pentafluoropropene was disclosed by Knunyants et al. (Chem. Abstr., 1961, 55, 349f). The yield of pentafluoropropane was 70%.
Burdon et al., J. Chem. Soc., C, 1969, 1739 disclose the formation of CF.sub.3 CH.sub.2 CF.sub.2 H, in low yield, during the elemental fluorination of tetrahydrofuran.
Commonly assigned U.S. Pat. No. 5,574,192 discloses the fluorination of CCl.sub.3 CH.sub.2 CHCl.sub.2 with HF/SbCl.sub.5 to produce HFC-245fa.
It is an object of this invention to provide a means of preparing 1-chloro-1,1,3,3,3 pentafluoropropane that is economical and amenable to large scale, using readily available raw materials.
It is a further object of this invention to provide a means of manufacturing 1,1,1,3,3-pentafluoropropane comprising reacting CF.sub.3 CH.sub.2 CF.sub.2 Cl with hydrogen in the presence of a reduction catalyst wherein the said CF.sub.3 CH.sub.2 CF.sub.2 Cl is prepared by reacting CCl.sub.3 CH.sub.2 CCl.sub.3 with hydrogen fluoride in the presence of a fluorination catalyst in either the liquid phase or the vapor phase.
It is a further object of this invention to provide a means of manufacturing 1,1,1,3,3-pentafluoropropane comprising the following steps:
1) the formation of CCl.sub.3 CH.sub.2 CCl.sub.3 by the reaction of CCl.sub.4 with vinylidene chloride; PA1 2) the conversion of CCl.sub.3 CH.sub.2 CCl.sub.3 to CF.sub.3 CH.sub.2 CF.sub.2 Cl by reaction with hydrogen fluoride (HF) in the presence of a fluorination catalyst either in the liquid phase or in the vapor phase; and PA1 3) reduction of CF.sub.3 CH.sub.2 CF.sub.2 Cl to CF.sub.3 CH.sub.2 CF.sub.2 H.
Each step is conducted under process conditions, i.e., temperature and pressure, sufficient to produce the desired product as discussed herein.